Power-driven components are becoming commonplace in motor vehicles as customers demand comfort and convenience. Power-actuated door latches and locks, hood releases, trunk openers, fuel-door openers, and hatches, for example, are either standard or optional equipment on many of today's cars and trucks. Customers looking to enhance their existing, non-powered equipment commonly turn to aftermarket components for conversion to power-driven equipment.
FIG. 1 is a schematic representation of a common solenoid actuator 5 known in the art for engaging a starter motor 6 with an engine 7. The solenoid actuator 5 includes a solenoid 2 and a plunger 13. The plunger 13 is coupled to a shift lever mechanism 8 that is linked to the starter motor 6. Electrical activation of the solenoid 2 linearly translates the plunger 13 which moves the shift lever mechanism 8 to move a drive component 9 of the starter motor 6 into engagement with a flywheel of the engine 7. When electrical energy is removed from the solenoid 2, the plunger 13 returns to a first position by the urging of a return spring 15 disengaging the drive component 9 from the engine 7.
The linear motion of the plunger 13 can be used to power other mechanisms that are normally manually operated from a first position to a second position. Examples of these other mechanisms include the opening/closing and locking/unlocking of door latches, hood releases, trunk openers, fuel-door openers, and hatches.
The solenoid actuator 2 coverts electrical energy to linear motion. FIG. 2 is a schematic representation of a common solenoid actuator 5, such as a starter or plunger-pulling solenoid actuator. The solenoid actuator 5 comprises a solenoid 2 and a plunger 13. The solenoid 2 includes a coil 1 which is a winding of wire defining a bore 3 adapted to accept the plunger 13. The plunger 13 is a magnetically-conductive elongated member, such as, but not limited to, an iron rod. At least a portion of the plunger 13 is received within the bore 3. The coil 1 is electrically energized by passing a current through the coil 1 which creates electromagnetic forces within the bore 3. The electromagnetic forces linearly translate the plunger 13 from a first position to a second position. Accordingly, when energized, the coil 1 generates a pulling force so that the plunger 13 is moved in the axial direction in a short period of time. A return spring (not shown) is coupled to the plunger 13 so as to urge the plunger 13 back into the first position after the current is removed.
FIG. 3 is a perspective view of a known pull-type solenoid actuator 10. The solenoid actuator 10 comprises a solenoid 2 including a cylindrical housing 11 that comprises the coil (not shown) defining a bore 3. Extending from the bore 3 is a plunger 13. The plunger 13 includes a plunger first end 17 that extends in the bore 3 and a plunger second end 18 that extends out of the bore 3. The plunger second end 18 includes an eyelet 14 which is a through-hole. The eyelet 14 is adapted to accept a hook-end of a lever, such as the shift lever of FIG. 1. A single eyelet 14 is not ideal for accepting a cable as will be discussed below.
FIG. 4 is a perspective view of a latching mechanism 50 coupled to a solenoid plunger 13 by a cable 30. The latching mechanism 50 comprises a lever 52, a pivot 54, a lever head 56, a restoring spring 55, and a locking notch device 58. The solenoid actuator 10 pulls the cable 30 that is coupled to the lever 52 to disengage the lever head 56 from the locking-notch device 58. Examples of latching mechanisms 50 include, but are not limited to, vehicle trunk lid latches, hood latches, and door latches. The solenoid actuator 10 provides remote operation of the respective latching mechanism 50. The solenoid actuator 10 is electrically energized by activating an electrical switch, such as a switch mounted in the cabin, or a button on a hand-held remote control transmitter, for example.
Known solenoid actuators 10 have a single eyelet 14 which are adapted to engage a hook on a lever, rather than adapted for use with a cable 30. This causes a number of significant problems in using solenoid actuators 10 for pulling a cable 30. One significant problem is that a single eyelet 14 does not provide the necessary adjustability for use as a cable-pulling device. This is particularly so when the solenoid actuator 10 is part of a conversion kit for hobbyist to install on their motor vehicles. A single eyelet 14 provides only a few choices for coupling the cable 30 to the plunger 13. FIG. 4 shows a crimping tab 32 coupled to the cable proximal end 31 of the cable 30 that extends through the eyelet 14. The crimping tab 32 is larger than the eyelet 14 and thus cannot pass through the eyelet 14 retaining the cable proximal end 31 to the plunger 13.
The crimping tab 32 is only as secure as the grip it has on the cable proximal end 31. The strong pull of the plunger 13 over many cycles puts much stress on the crimping tab 32 leading to eventual slippage and failure. Considering that the length of the cable 30 is unique and determined by the specific application, the crimping tab 32 is coupled to the cable proximal end 31 by the installer. Lack of skill in assembly will also contribute to premature failure of the crimping tab 32.
FIG. 3 shows another configuration for coupling the cable 30 to the plunger 13. The cable proximal end 31 is formed into a loop 35 with the crimping tab 32 coupled to the cable proximal end 31 and to another portion of the cable 30. Forming a loop 35 in the cable proximal end 31 provides an easier assembly for the installer. Crimping the crimping tab 32 onto another portion of the cable 30 may relieve some of the stress on the crimping tab 32 as compared with the crimp shown in FIG. 4.
In application, the looped cable proximal end 31 is problematic over time. After a number of cycles, the loop 35 stretches and enlarges. This not only causes the cable 30 to slacken, but also interferes with proper function. An oversized loop 35 can shift in the eyelet 14. FIG. 5 illustrates a loop 35 having turned retrograde in the eyelet 14. This causes the cable 30 to shorten significantly usually resulting in the latching mechanism 50, such as shown in FIG. 4, remaining in the open position. Disassembly of a motor vehicle body panel and retightening of the cable 30 is usually required to remedy the failure.
It is desired in the art to have a solenoid actuator for use in pulling a cable that addresses the problems associated with currently-available solenoid actuators. It is desired to provide a solenoid actuator that allows for greater adjustability for coupling a cable to the plunger. Further, it is desired to provide a solenoid actuator that overcomes the problem of a cable loop becoming retrograde preventing operation of the attached mechanism. Further, there is a need for a solenoid actuator that is easy to install, regardless of the application. There is also a need to reduce specialization of solenoid actuators, providing more universal designs which results in lower costs per unit, greater flexibility in the number of applications, and improved economies of scale for the manufacturer.